THE SEARCH FOR SUSTAINABLE TRANSPORT: ANTICIPATING AMERICANS VEHICLE & TRAVEL CHOICES Kara Kockelman Professor of Transportation Engineering, UT Austin
Introduction Climate & energy security are key concerns for most countries. Per-capita GHG emissions in U.S. are four times the world average, with transportation accounting for 30% of the nation s total. Plug-in electric vehicles (PEVs) have emerged as important alternatives. Some key questions: What are emerging PEV designs? Who will be buying & driving PEVs? What are typical use patterns? What are the emissions impacts?
Some PEV Designs Make & Model Release Date Retail Price (after credit) Body Type Range-Extended PEVs Chevy Volt erev 2010 $33,500 4-door sedan Toyota Prius PHEV 2012 $29,500 4-door sedan Ford CMAX Energi 2013 Est $30,000 4-door CUV Battery-Electric Vehicles (BEVs) Tesla Roadster 2009 $101,500 2-door sports car Nissan LEAF 2010 $25,250 4-door sedan Mitsubishi i (MiEV) 2011 $21,625 4-door sedan Ford Focus 2012 $31,700 4-door sedan Tesla Model S 2012 $49,900 4-door sedan Battery (kwh) Estimated SOC AER (miles) 16 65% 35 4.4 Est 50% 11 Est 10 Est 70% Est 20-25 53 80%+ 240 24 90%+ 73 16 TBA 100 23 TBA 100 42 80%+ 160
Extended-Range EVs (erevs) Battery + internal combustion engine (ICE). Electrical energy provided by battery initially, & by ICE when battery is depleted. Example: Chevy Volt (2010) Price: $33,500 (after credit) Electric Range: 35 miles (EPA)
Battery Electric Vehicles (BEVs) Large on-board battery provides all motive power. Charge while parked via electric power cord. Range anxiety is an issue. Example: Nissan Leaf (2011) MSRP: $25,250 (after credit) Range: 73 miles (EPA)
Plug-in Hybrid EVs (PHEVs) Similar to HEVs, but bigger batteries & can be charged using power grid. Typically operates in blended mode, with both gas engine & electric motor working simultaneously. Example: Prius PHEV (2012) Price: $29,500 (after credit) Electric Range: 11 miles
Motivation: We need to know How many households can make do with a rangelimited BEV? What share of a household s VMT will be electrified when adopting a PHEV? What cost savings can households expect from a PEV? How quickly will households be buying these? What effect will they have on GHG emissions? Such info allows manufacturers to better predict demand, many consumers to overcome range & cost concerns, & policymakers to make decisions.
Seattle s Multi-day GPS Data Multi-day data reflect Americans great variability in day-to-day vehicle use. GPS data collected from 424 vehicles (264 households) in Seattle region between November 2004 & April 2006, for about 340 days each. Average miles-driven per day is 25.4 12.3 miles (across all vehicles & days). Population weights were used to reflect Seattle population.
Analysis Framework Household Single-vehicle household Multiple-vehicle household Switch to a BEV (Case 1) Switch to a PHEV (Case 2) Switch a vehicle to a BEV Switch a vehicle to a PHEV What percentage of the days can all mileage be covered? What percentage of miles are electrified? Which vehicle to switch? Which vehicle to switch? The vehicle that travels less on average (Case 3) The vehicle that travels less on any given day (Case 4) The vehicle that travels more on average (Case 5) The vehicle that travels more on any given day (Case 6) What percentage of the days can the entire mileage be covered? What percentage of the days can the entire mileage be covered? What percentage of miles are electrified? What percentage of miles are electrified?
% of Households BEV Accommodation: 1-vehicle HHs 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 90% of days 95% of days 99% of days Nissan Leaf (73 mi AER) 50 60 70 80 90 100 110 120 130 All Electric Range (AER), in miles Maximum Possible Single-vehicle Household Accommodation Shares with BEVs in Seattle (Case 1)
% of Households BEV Accommodation: Multi-vehicle HHs 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 90% of days 95% of days 99% of days Nissan Leaf (73 mi AER) 0% 30 40 50 60 70 80 90 100 110 120 130 All Electric Range (AER), in miles Maximum Possible Multiple-vehicle Household BEV Accommodation Shares in Seattle, with BEV Replacing the Lower Overall-VMT Vehicle (Case 3)
% of Household VMT Electrified Average Shares of Total Household Miles Electrified (with Std. Devs.) using PHEVs in Multiple-vehicle Seattle Households PHEV Electrified VMT: Multi-vehicle HHs 90% 80% PHEV assigned day-to-day Highest average-vmt vehicle replaced by PHEV 70% 60% 50% 40% 30% 20% 10% 0% Prius PHEV Chevy Volt 0 10 20 30 40 50 60 70 All Electric Range (AER), in miles
Annual Cost Savings: Volt vs. Cruze Electricity Prices (ct/kwh) Annual Savings Gas Price Assumptions $2.50/gallon $3.50/gallon $4.50/gallon $5.50/gallon $6.50/gallon Vehicle is driven on average 15 miles/day, & 4,315 miles/year 6.0 $252 $383 $514 $645 $776 11.2 $188 $319 $449 $580 $711 16.0 $128 $259 $390 $520 $651 Vehicle is driven on average between 15 & 30 miles/day, & 8,056 miles/year 6.0 $453 $686 $919 $1,153 $1,386 11.2 $340 $573 $806 $1,039 $1,273 16.0 $235 $468 $702 $935 $1,168 Vehicle is driven on average more than 30 miles/day, & 14,886 miles/year 6.0 $734 $1,105 $1,475 $1,846 $2,217 11.2 $567 $937 $1,308 $1,679 $2,050 16.0 $412 $783 $1,154 $1,524 $1,895 Note: $33,500 Volt (after $7,500 credit) uses 36 kwh per 100 miles, & enjoys a 37 mpg (once battery is depleted). The $22,225 Cruze LTZ is rated for 28 mpg. Cruze navigation system costs $995. Net price difference is $9,560.
Net Present Value: LEAF vs. Versa Gasoline Price ($/Gallon) $7.00 $6.50 $6.00 $5.50 $5.00 $4.50 $4.00 $3.50 $3.00 $2.50 $0 No Battery Replacement $18,128 $16,398 $14,668 $12,938 $11,208 $9,478 $7,748 $6,018 $4,288 $2,558 Replacement Battery Price ($ per kwh) $150 $250 $350 $450 $15,807 $14,077 $12,347 $10.617 $8,888 $7,158 $5.428 $3,698 $1,968 $238 $14,260 $12,530 $10,800 $9,070 $7,340 $5,611 $3,881 $2,151 $421 ($1,309) $12,713 $10,983 $9.253 $7,523 $5,793 $4,063 $2,333 $604 ($1,126) ($2,856) 15yr/150k mile $11,166 $9,436 $7,706 $5,976 $4,246 $2,516 $786 ($944) ($2,673) ($4,403)
Findings from Seattle GPS Study BEVs appear feasible for significant shares of households, with relatively little behavioral adjustment. Electrified-miles shares are sizable. Without tax credits, the relative NPVs are typically negative at $3/gallon (gas prices at time of analysis). Cost savings may be substantial for longer-distance drivers who electrify more of their miles and is estimated to be strongly positive for those in higherfuel-cost regions (e.g., Germany at $7 to $8 per gallon).
Austin Energy & Fleet Survey Results Who supports what, & what may our fleet look like in 30 years?
Austin Energy, Travel & Vehicle Surveys Survey Design & Distribution in Fall 2008 & Spring 2009 Hard copy + Online versions Topics: Travel Choices, Vehicle Ownership, Home Design & Energy Use, Energy Policy Opinions, Vehicle Purchase & Retirement Plans, & Demographic Attributes Sample Attributes vs. Austin PUMS: Workers underrepresented & students over-represented Sample corrected via weights across income, gender, age, household size, & worker & student status
What Should We Do about Climate Change?
Key Austin Energy Survey Findings Policy of adaptation (to climate change) more often preferred by workers & households owning many vehicles. Regulation of energy use more often preferred by women & homeowners. Caps on household energy use preferred to taxes. Long-term behavioral changes are difficult to implement. Most agree that climate change is a concern, but are unwilling to change their own behavior. Increasing income & education levels lead to greater (stated) concern about one s impact on the environment.
Vehicle Survey: Top Three Attributes
Austin Vehicle Type Choice With gas at $5/gallon, Prius HEV was top choice (27%). At $7/gal, Prius PHEV with 40 AER was topper (29%). When providing info on environmental costs, PHEV (25%) was top choice, followed by Compact cars (23%).
Million Lbs * % s are Changes from TREND Scenario Austin Transport-based CO 2 (2034) 30,000-3.77% * +0.29% * 25,000-22.02% * 20,000 15,000 10,000 5,000 0 Trend Scenario (TREND) Feebates (FEEBATE) Gas at $5/gallon (Pricing) Optimistic PHEV Incremental Pricing (LOWPRICE) Unfortunately, simulation predicts almost a TRIPLING of persontravel-related GHG emissions vs. base year, under TREND.
The Nation s Fleet Evolution Modeling Household Choice Behavior over the Long Run
US Fleet Evolution: Some Survey Results 18%, 5.5%, & 2.3% of American households state that they intend to acquire a vehicle, replace a vehicle, or dispose a vehicle within 1 year. High purchase price is top reason for not buying certain vehicles they had considered recently. 42% would consider paying $3,000 more to buy a HEV version of a conventional vehicle. 36% expressed interest in buying a PHEV at $6,000 more than comparable ICE (vs. 56% Austinites). 56% have power access in a garage or carport. Just 29% of respondents support a feebate policy (vs. 63% of Austinites).
Percentage Current Ownership & Coming Choices 25 20 15 10 5 0 Sub Compact Compact Midsize Large Luxury Van SUV CUV Pickup Stated-preference questions offered 12 vehicles (with info on price & fuel economy, plus links to online details): 9 conventional (above) + Prius HEV, Prius PHEV30, & SmartCar.
% Respondents Coming Vehicle Choices 30 25 20 15 10 Trend Gas at $5 per gallon Gas at $7 per gallon Environmental costs provided 5 0 Environmental-cost scenario s results closely mimic those of $5/gal scenario, though environmental costs presented are far lower. Simple labeling or astute advertising may shift perceptions quickly in the direction of a cleaner fleet.
Analysis of the Choice Data A variety of behavioral model specifications were estimated (e.g., MNL for transaction, NL for vehicle choice, & WLS or Heckit for use). Households in survey sample were scaled up using population weights to generate a synthetic population of 50,000 households. The simulation anticipates each household s vehicle holding decisions & type of vehicle to be acquired/disposed, along with use (annual VMT), on a yearly basis, relying on Monte Carlo draws.
Modeling Framework HH Population at Time t HH Exit Model (Out-Migration & Death) HH Birth Model (In-Migration, Divorce & Leaving Home) Vehicle Ownership Model HH Transitions Marriage, Divorce, Child Birth & Leaving Home Transaction Decision Model Buy Sell Replace Do Nothing Stated Preference Vehicle Choice Model Lowest Utility Vehicle Disposal Lowest Utility Vehicle Disposal Stated Preference Vehicle Choice Model Update Household Vehicle File, HH Population at time t +1 Vehicle Usage Model & GHG Emissions
Simulating the Future Micro-simulation predicts future fleet mix, overall usage, & associated emissions from 2010 through 2035. Scenarios TREND: Status quo/business-as-usual. LOWPRICE: Price of PHEV lowered by $4,100. FEEBATE: Rebates/fees to vehicles over/under 30 mpg at an average rate of $200 per mpg. FEEBATE2: Rebates/fees to vehicles over/under 30 mpg at an average rate of $400 per mpg. HI-DENSITY: Quadrupled job & household densities. LAYERING of LOWPRICE, FEEBATE, & FEEBATE2 scenarios with GASPRICE at $5 per gallon. GASPRICE$7: Gasoline at $7 per gallon.
Percentage US Fleet-Mix Predictions for 2035 35 30 25 20 15 10 5 0 TREND LOWPRICE FEEBATE FEEBATE2 HI-DENSITY LOWPRICE+GAS5 FEEBATE+GAS5 FEEBATE2+GAS5 GASPRICE$7
CO2e Emissions (Million Pounds) 2035 US Greenhouse Gas Emissions 3000 2500 2000 1500 1000 500 0
Results: US Fleet Simulation $7/gallon gas prices had greater impact on vehicle ownership & miles than any other policy examined (including feebates & combined feebate-phev price drop). Changes in fleet mix, VMT, & emissions predicted via simulation are far less than needed to tackle environmental & energy security issues. More widespread use (of PEVs & HEVs) may emerge with strategic & pronounced marketing, technological advances (lower prices), as well as other incentives (e.g., HOV lane & fast-charge access) & greater awareness of energy & climate issues.
Urban Systems Forecasting Modeling Household & Firm Location Choices, Land Use Patterns, Land Development, Travel Choices, Emissions & Air Quality
Example HH Population at time t Framework Firm Population at time t HH Exit Model (Out-Migration & Death) HH Birth Model (In- Migration, Divorce & Leaving Home) Firm Death/Exit Model Firm Birth Model HH Transitions Marriage, Divorce, Child Birth & Leaving Home Vehicle Ownership, Transactions Model HH Location, Type Choice Model Firm Expansion/ Contraction Model Firm Relocation Model Firm Location Choice Model HH Population at time t+1 Firm Population at t+1 Electricity & Natural Gas Consumption HH Trip Generation, Distribution Commercial Trip Generation & Distribution Electricity & Natural Gas Consumption External-External & External-Internal Trips Network Equilibration (& Gasoline Consumption) CARBON EMISSIONS
Austin Policy Scenarios Business as Usual or trend scenario (BAU) Urban Growth Boundary (UGB) Increase Travel Costs ($6/gallon & toll 10 cents/mile) (PRICING) Doubled Capacity of Austin s IH-35 (EXPCAP) Introduction of a New East-side Freeway (SH130). Austin UGB
2030 UGB 2005 Base Year 2030 BAU HH density - # per square mile
Results: Land Use Statistics (year 2030) BAU UGB PRICING EXPCAP SH130 CBD Accessibility 962,045 1,020,487 929,141 937,912 938,026 Count-weighted Household Density Count-weighted Jobs Density 3,608 5,460 3,072 3,525 3,565 14,810 15,093 14,288 16,893 14,460
Results: GHG Emissions per capita Year 2030 estimates BAU UGB PRICING EXPCAP SH130 TRANSPORTATION ENERGY Daily VMT (million) 94 81 90 100 103 Daily CO2 (million lbs/day) 95 83 91 101 98 CO2 emissions per capita (tons/yr) 5.51 4.82 5.28 5.86 5.69 Annual VMT per capita 10,293 8,993 9,859 10,943 10,618 RESIDENTIAL ENERGY CO2 from electricity (million lb/yr) 18,648 17,018 18,569 18,578 18,974 CO2 from natural gas (million lb/yr) 2,868 2,777 2,840 2,857 2,833 CO2 emissions per capita (tons/yr) 4.16 3.83 4.14 4.15 4.22 TOTAL CO2 per capita (tons/year) 9.68 8.65 9.42 10.01 9.91
Ozone Modeling for Austin UGB & Toll+Tax policies result in 15% savings in VMT, NOx & HC.
Collaborators: Moby Khan David Tuttle Sashank Musti Binny Paul Siva Kakaraparthi Sumala Tirumalachetty Brenda Zhou & Others Thank you! Questions & Suggestions? Papers available at www.ce.utexas.edu/prof/kockelman